Apple reportedly tweaked the iPhone to work better on AT&T

AT&T continues to improve its network to handle the traffic that iPhone users …

Since the original iPhone launch, AT&T has put in motion a number of upgrades to its wireless network to accommodate the pounding it received at the collective fists of millions of iPhone users. But according to AT&T CTO John Donovan, Apple has also done its part to adjust the iPhone to work better on AT&T's network.

Donovan told the Wall Street Journal that, even as the company worked to convince Apple that it was improving its network, AT&T engineers went to Apple to give Apple's engineers a "crash course" in wireless networking. Apple modified how the iPhone communicates with towers to reduce the overhead for making connections or sending texts.

Ars contacted both AT&T and Apple for further details about what was changed, but neither company offered any specific information. We do know, however, that the the iPhone—as well as smartphones that came after it—uses certain techniques for saving battery power that can bog down signaling channels on cell towers that aren't configured to handle signaling loads dynamically. The last we heard about significant changes in the 3G networking capabilities of the iPhone OS was in late 2008, though it's sure that Apple since tweaked the network stack whenever needed.

AT&T learned that hard way that iPhone users didn't add network traffic in the same predictable patterns as users of other phones did. The company "is managing volumes that no one else has experienced," Donovan said. The growing pains that AT&T experienced as the iPhone skyrocketed to the top of the smartphone market in the US have left a number of users frustrated, with many willing to jump to another carrier if it could offer service for the iPhone. Half of Ars readers using an iPhone said they would switch to Verizon if a rumored CDMA-compatible iPhone materialized soon.

Verizon CTO Anthony Melone bragged late last year that the company was more than ready to handle the onslaught that iPhone users would bring to the network. "We are prepared to support that traffic," Melone told BusinessWeek.

That's easy to say, AT&T spokesperson Seth Bloom told Ars, "but the truth is no one knows what their network would look like if they had the iPhone." "Of course, it's true that others have been able to watch what we've done to handle a 5,000 percent surge in data traffic," Bloom added. "But watching is quite different from doing."

Bloom said that the upgrade to HSPA 7.2 and the added backhaul—"enough to also support our LTE buildout"—will keep AT&T ahead of the competition, which may be enough to keep iPhone users from looking at other carriers. "More and more people are going to get the benefits of 7.2 speeds this year on our network," he said.

I often wonder why that if the highest cost of upgrading backhaul bandwidth is the physical labor involved in laying the cable, why companies still say things like "enough to also support our LTE buildout" instead of "enough to also support 50 times our LTE buildout".

The company "is managing volumes that no one else has experienced," (...) "but the truth is no one knows what their network would look like if they had the iPhone."

And this is literally bogus - there are other countries where the iPhone has exclusive carriers, and in Portugal there are 2 carriers for iPhone. According to previous coverage in Ars, not all networks experienced the problems with dropped calls seein in AT&T's network.

I just wish AT&T (and all mobile carriers) would get this one simple fact:

Their "phone" network needs to be a DATA network that handles voice traffic as part of the overall data bandwidth, rather than a VOICE network with data bolted on in rather shoddy fashion. Based on what I read at WSJ and here, it seems that AT&T is slowly getting the idea, but they're cloaking it in terms of "oh hey, let's point the antennas up instead of down".

Any radio operator worth their salt knows to stick your antennas on the high ground. You'd think that in cities like NYC, Chicago, or SF they'd already be on every other high-rise.

The only bright spot was the admission that network upgrades are scheduled for certain timeframes based on the demographics of the majority of users in that area. That actually demonstrates customer orientation.

@RandyHall it's not that simple. A tower at the top of a Manhattan skyrise can't serve all the people in the building across the street. Not even close. It's the 3-dimensional nature of such cities that challenges the normal hex-grid or square-grid network architecture that works fine in the suburbs.

As a user of android on Verizon I must say that the phone/3G data is topnotch. It really does work everywhere. Its crazy. Anyone who is suffering with an unreliable connection just to have an Iphone is nuts. (actually nuts is to harsh because I think you don't realize how much better it is until you switch).

Am I wrong in thinking that the reason the iPhone in the USA is tied to AT&T is that the current iPhone is a GSM-only phone, and AT&T has the only GSM network?

Here in Luxembourg where all cell phones are GSM, we have 3 competing service providers, all support the iPhone, and all iPhones are unlocked. I've never been aware of any network congestion issues. Competition is a great thing.

I think the biggest April Fool will be AT&T. If they honestly think hoarding the iPhone for 3 years, plus years of crappy service, years of overpriced services, & Ralph De La Vega wanting to add tiered pricing for data, then I honestly want whatever AT&T is smoking. There's no way on God's green Earth I'd ever go back to AT&T even if it does have 3G fully capable Jesus phone.

My best friend was responding to an Ars article I placed about the iPhone with this simple message. "My iPhone's 3G connection just died." This was AFTER AT&T put the HSPA 7.2 in the Dallas market. Guess what AT&T, IT DIDN'T WORK! Their service is still just as crappy as pre-HSPA 7.2.

That's why I'm on Sprint. Sprint does suck at customer service, but their network is excellent! I am always connected at 3G voice & EV-DO data speeds. I never have to worry about the network, I just do things with my phone. It works & it's done. I went on vacation last summer with my phone & it worked well in California. Didn't have to worry. Can iPhone users say the same? Not in the last 3 years.

I just hope AT&T users "don't get fooled again" by Luke Wilson & empty promises. AT&T needs to go down in flames for awhile & really do the hard work of fixing their issues.

I just wish AT&T (and all mobile carriers) would get this one simple fact:

Their "phone" network needs to be a DATA network that handles voice traffic as part of the overall data bandwidth, rather than a VOICE network with data bolted on in rather shoddy fashion. Based on what I read at WSJ and here, it seems that AT&T is slowly getting the idea, but they're cloaking it in terms of "oh hey, let's point the antennas up instead of down".

Any radio operator worth their salt knows to stick your antennas on the high ground. You'd think that in cities like NYC, Chicago, or SF they'd already be on every other high-rise.

The only bright spot was the admission that network upgrades are scheduled for certain timeframes based on the demographics of the majority of users in that area. That actually demonstrates customer orientation.

Both GSM/UMTS and CDMA2000 has evolved into data only variants: HSDPA (HS*PA, etc.) and EVDO. However, they still look "bolted on". And neither data network is at the point where they can reliably do VoIP, even to the low standards of cell phones.

The real problem is that AT&T just hasn't deployed the infrastructure - neither backbone or basestations.

In urban environments, you want to "point the antennas down", to shrink the cell sizes and decrease inter-cell interference. Antenna placement and angles is a very hard problem, where you trade off coverage vs. cell interference.

Am I wrong in thinking that the reason the iPhone in the USA is tied to AT&T is that the current iPhone is a GSM-only phone, and AT&T has the only GSM network?

Here in Luxembourg where all cell phones are GSM, we have 3 competing service providers, all support the iPhone, and all iPhones are unlocked. I've never been aware of any network congestion issues. Competition is a great thing.

There's T-Mobil in the US, but they've been behind everyone else in deploying 3G.

I still don't trust the "signalling channel" reasoning. I actually do have a an M.S. in Telecom and spectrum is spectrum (yeah I went to grad school and all I learned was that, oops). Seriously though, you can redefine the amount of signalling vs. data channels as needed. Worse case scenario - you look at tower analytics and increase signal channeling as necessary on a say, monthly basis. Best case, you have hardware that is programmable or "smart" and can dynamically allocate spectrum based on load. Of course, constant reconfiguration of the radio requires CPU cycles that are usually used for other items on the agenda. Also, RF front-ends configured for data-heavy transmission can have issues differentiating huge amounts of channel neighboring signalling vs. fewer big, stable data channels. I imagine AT&T has both type of radios and the HSDPA 7.2 upgrades are piggybacking the root reason of installing radios that can reconfigure intelligently.

Am I wrong in thinking that the reason the iPhone in the USA is tied to AT&T is that the current iPhone is a GSM-only phone, and AT&T has the only GSM network?

Here in Luxembourg where all cell phones are GSM, we have 3 competing service providers, all support the iPhone, and all iPhones are unlocked. I've never been aware of any network congestion issues. Competition is a great thing.

The only other GSM carrier in the US is T-mobile, but their 3G deployment is on a frequency that the iPhone doesn't support. There are lots of people that have unlocked iPhones and using T-mobile SIMs, but they are limited to EDGE speeds.

The growing pains that AT&T experienced as the iPhone skyrocketed to the top of the smartphone market in the US

The iPhone is ahead of Blackberry's and Symbian devices?

In the US, Symbian is practically non-existent. The iPhone is the number one selling device, but all of RIM's sales collectively are still ahead of Apple's in the US and globally. But Apple grew much faster than RIM in 2009, and may surpass its sales sometime in 2010.

The company "is managing volumes that no one else has experienced," (...) "but the truth is no one knows what their network would look like if they had the iPhone."

And this is literally bogus - there are other countries where the iPhone has exclusive carriers, and in Portugal there are 2 carriers for iPhone. According to previous coverage in Ars, not all networks experienced the problems with dropped calls seein in AT&T's network.

Well, in terms of percentages I think that other countries are far ahead, but in terms of sheer numbers I believe that AT&T has the most iPhone users on a given network.

I just wish AT&T (and all mobile carriers) would get this one simple fact:

Their "phone" network needs to be a DATA network that handles voice traffic as part of the overall data bandwidth, rather than a VOICE network with data bolted on in rather shoddy fashion.

Yeah, they get it. It's called "LTE."

Oh, snap. Really though, while LTE is going to cause less headaches in the long run by going completely IP and using better spectrum, it's not absolutely necessary in terms of data speeds to the consumer. In truth, it's all about backhaul. Fiber to the Tower instead of ass-tackular T1s would make all the difference in the world. Remember that HSDPA can support up to 21 Mbps; and that can be extended with channel bonding. On the client side, most phones just need a firmware update to support 21 Mbps as Tmobile is demonstrating. In the field, LTE is only going to see about 4.5 Mbps. The short-term fiscal impetus pushing the expensive and geographically targeted 700 MHz purchases by cell carriers is to pursue LTE as a last mile technology for houses without cable or DSL.

AT&T said the same thing months ago and the Apple comment was something a long the lines of "bullshit!".

AT&Ts network wasn't prepared for people to actually use their data plans. Big surprise. The user experience on other phones was so poor that people only used them to the extent they had-to. Where as the user experience on the iPhone was such that users wanted to use them.

AT&Ts biggest problem in this was their PR handling and denying it was their problem in the first place.

As a corporate user of a Moto Droid and an iPhone for personal use. I can speak to what matters, functionality. As far as Exchange goes Android needs some real improvement. All the exchange mail comes down as plain text. I know, there's Touchdown, but I want the mail to look like the way it was sent, the way it looks on the iPhone. And i'll be damned, want to review a document you just received and access email again while on the phone with your client/customer/peer. Let me DL it and call you back. So please lets stay in the realm of reality here and not pretend like just because its not on AT&T the world is a better place. Sheesh.

The only other GSM carrier in the US is T-mobile, but their 3G deployment is on a frequency that the iPhone doesn't support. There are lots of people that have unlocked iPhones and using T-mobile SIMs, but they are limited to EDGE speeds.

Actually there are quite a few GSM carriers in the United States, but many seem to exist only to siphon roaming fees off other carriers' users (I think Caprock in Texas and Epic Touch in Kansas may qualify). There are also some regional carriers like Airadigm (Einstein Wireless) in Wisconsin and Corr in northeast Alabama that sell GSM service in small geographical areas. AT&T users will only see "AT&T" on their display even when roaming on these networks, but T-Mobile SIMs will show the actual carrier name, which as a phone nerd I prefer.

We seem to be at a point with UMTS in phones like GSM was back in the late 90's: every phone only supported two or three global bands and not the full slate of global allocations. Is it a lack of technological prowess to squeeze more UMTS bands into a phone, or just carrier-locking laziness? I'd love to have a Nexus phone but T-Mobile doesn't serve my area. I'd get EDGE with AT&T but no 3G because it doesn't support their band. D'oh. (The solution? I'm going to move to another state where T-Mobile works!)

I still don't trust the "signalling channel" reasoning. I actually do have a an M.S. in Telecom and spectrum is spectrum (yeah I went to grad school and all I learned was that, oops). Seriously though, you can redefine the amount of signalling vs. data channels as needed. Worse case scenario - you look at tower analytics and increase signal channeling as necessary on a say, monthly basis. Best case, you have hardware that is programmable or "smart" and can dynamically allocate spectrum based on load. Of course, constant reconfiguration of the radio requires CPU cycles that are usually used for other items on the agenda. Also, RF front-ends configured for data-heavy transmission can have issues differentiating huge amounts of channel neighboring signalling vs. fewer big, stable data channels. I imagine AT&T has both type of radios and the HSDPA 7.2 upgrades are piggybacking the root reason of installing radios that can reconfigure intelligently.

I suspect the issue is coordinating spectrum usage across devices. Suppose you have N phones that are in range of a particular base station. Now whether or not these phones are currently transmitting any information you have to allocate (via orthogonal codes=CDMA, time=GSM or frequency) some portion of your total bandwidth in the next second to each phone so that if it chooses to send some new data to the tower it can do so without disrupting other phones. Moreover, the more data you want a particular phone to have the ability to transmit during the next second the larger fraction of bandwidth during that section you need to set aside for potential transmissions from the phone.

Of course if you had information theoreticly optimal protocols (perfect statistical models of whether a given phone would need to transmit at any given time) then there would be no loss of bandwidth to phones that don't then transmit. After all you know the true probability of transmission at any given time by any phone so it's just like any other bit of information. Practically speaking however you can't do anything of the kind. All the devices have to agree on who gets to transmit what and don't have access to the content of other phones communications with the tower so if the tower wants to dynamically decrease the bandwidth allocated to a particular device and assign it elsewhere it must waste bandwidth coordinating this change between the phones (you now can transmit at these times/codes).

So now suppose that the iphones use bandwidth in a way that's very hard for the towers to predict, e.g., starts sending huge amounts of data in second 1..5 then nothing in second 6 where the tower is guessing that this phone still needs a bunch of bandwidth. You end up wasting bandwidth assigned to phones who don't need it. If instead the phone is set up to use bandwidth predictably, e.g., notify the tower in advance of it's mail checking sync and predictably inform the tower it's finished it's sync then most of that bandwidth in second 6 could be allocated to other phones.

In other words information theory tells us that the more unpredictable a bitstream is the more bandwidth it uses up. The amount of data a phone will send in any second is part of the information content of that link therefore making data usage easier to predict decreases the amount of bandwidth needed.

What might have happened is that the tcp/ip streams the iphone sent caused it to constantly ask the tower for more/less bandwidth sending all sorts of control signals that a more predictable network stack could simply do without.

> AT&T better improve for the next phone or else I think they will see people defecting

AT&T should have improved YEARS ago.

Do you really think AT&T was "totally unaware" that the iphone was selling like crazy in 2007?And data loads were EXTREMELY heavy.And things got worse and worse in 2008.And millions of more iPhones were sold in 2009.